1. Field of the Invention
This invention deals with additives which are particularly useful in refinery operations for adding a alkali metal or alkaline earth metal containing compound to an unleaded gasoline for valve seat recession protection.
2. Description of the Art
It is known from Graham et al, U.S. Pat. No. 3,955,938 issued May 11, 1976 that automobile valve seats, particularly on older model cars, require protection to avoid excessive wear. The valve seat recession problem is particularly severe in vehicles which were designed to run on leaded fuels and which must now use unleaded fuels. Graham suggested the introduction of a sodium and phosphorus-containing compound to an unleaded gasoline to provide valve seat recession protection. In U.S. Pat. No. 4,659,338 issued Apr. 21, 1987, Johnston and Dorer, suggested that a low lead or no lead containing gasoline incorporate a hydrocarbon-soluble alkali or alkaline earth metal-containing composition and at least one hydrocarbon-soluble ashless dispersant.
It is observed that the over-based composition suggested by Graham is particularly susceptible to separation into water found in a refinery, a fuel storage tank or an automobile fuel tank. To some extent, the problem of leaching of the composition into an aqueous phase also exists with the neutral or slightly acid forms of the composition.
It has further been observed that the source of the alkali metal or alkaline earth metal containing composition and a hydrocarbon-soluble ashless dispersant may emulsify. That is, when a mixture of the alkali or alkaline earth metal, a hydrocarbon-soluble ashless dispersant and water are subjected to high shear an emulsion can occur. The emulsification is particularly deleterious when a fuel filter in a vehicle becomes plugged or that the emulsification results in the loss of the active species, e.g., the alkali metal or alkaline earth metal, which is then not delivered to the vehicle in the requisite amount. The emulsification problem is particularly evident under refinery conditions where substantial volumes of water are present due to processing and where high speed pumps are used to deliver the refined gasoline via a pipeline.
The present invention deals with a particular group of nitrogen-containing esters which are useful as demulsifiers or stabilizers of the product in the fuel phase, thus, minimizing the effect of shear. It may also be viewed in the present invention that the demulsifier aids in separating any emulsified active ingredient from the aqueous phase back to the fuel phase.
Various nitrogen-containing or ester compositions have been utilized in fuel or lubricant containing products. For instance, in U.S. Pat. No. 3,362,906, issued Jan. 9, 1968 to Cyba, it is disclosed that lubricants and hydrocarbon oils may be stabilized against deterioration by means of a reaction product of an alkanolamine with a polyhalopolyhydropolycyclicdicarboxylic acid or its anhydride or ester. It is also known from U.S. Pat. No. 3,088,815, issued May 7, 1963 to Haney that fuel degradation particles may be avoided by reacting approximately equal molar portions of a dibasic acid or its anhydride or ester with an alkyl substituted dialkanolamine.
In U.S. Pat. No. 3,183,070, issued May 11, 1965 to Udelhofen, it is suggested that hydroxy amine esters of succinic acid provide benefits against rust and corrosion in storage tanks, valves, pipelines, tank car walls, burners, gasoline tanks and crankcases. Delafield et al, in U.S. Pat. No. 3,658,707, issued Apr. 25, 1972, suggests that gasoline compositions may be improved through the use of a mixture (1) of carboxylic acids containing from 10 to 60 carbon atoms per molecule, or esters or anhydrides of such acids and (2) esters of alkoxylated phenol-aldehyde resins.
In U.S. Pat. No. 2,944,025, issued July 5, 1960 to Verdol, it is suggested that a hydrocarbon oil may be formed from a dibasic acid which is reacted with an alkyl substituted diethanolamine. The products of Verdol are stated to be particularly useful as low temperature dispersants in mineral oils of lubricating viscosity.
The present invention deals with a problem which has not been previously recognized in the art, namely, to incorporate an alkali metal or alkaline earth metal containing material for valve seat recession in a low lead or unleaded gasoline, and to ensure against substantial loss of the active ingredient through contact with water. The present invention solves the foregoing problem through the incorporation of a nitrogen containing ester which functions as a demulsifier.
Throughout the specification, percentages and ratios are by weight, temperatures are in degrees Celsius, and pressures are KPa gauge unless otherwise indicated. To the extent that the references cited herein are applicable to the present invention, they are incorporated by reference.